Billionaire offer to clean Bhopal derided as front for chemical firm

One of India's richest men has been lobbying for the Indian government to drop a court case against an American multinational to pay for the clean up costs of the world's worst chemical accident, according to letters obtained by campaigners.

The documents, acquired under India's right to information law, show industrialist Ratan Tata writing to ask whether the Indian government could "withdraw [an] application" to make Dow Chemicals pay $22m [£12m] as an initial deposit against "environmental remediation costs".

Dow owns Union Carbide, whose pesticide plant leaked deadly white gas killing thousands in Bhopal in 1984. The company claims it bears no liability for the site as it has since sold up and left India.

After an international outcry that the site had not been decontaminated more than 20 years on, the Indian government launched a legal case to recoup money from Dow in May 2005. Campaigners say there is evidence that the disused plant still has 170 tonnes of toxic waste leaching into the soil and poisoning groundwater.

Studies show that 57 out of 120 children who grew up near the abandoned plant suffered from cerebral palsy. More than 26,000 people still drink "dirty" water.

Mr Tata, who runs the £30bn Tata group, says his company could break the "dead lock" and fund a clean-up of the site.

A letter from Dow says it is "critical" the government of India drops its legal action and that the resolution of the issue must be seen as a "tangible, deliverable outcome" of a newly formed US-India business forum which Mr Tata oversees.

Tata group said its chairman's suggestions were "totally independent of the issues being addressed in the courts. It is imperative some initiative be undertaken to clean the site."

Campaigners said Dow Chemicals was using an "Indian front company to do its dirty work".